The present invention is particularly applicable to use in pipe welding and particularly for tandem electrodes or side-by-side electrodes used in pipe welding and it will be described with particular reference thereto; however, the invention has much broader applications and may be used for single electrode electric arc welders requiring extremely high current levels, such as welding currents exceeding about 1000-2000 amperes.
Electric arc welders for pipe welding and other similar applications often require welding currents in excess of 1000-2000 amperes. In the past, welders for developing such high welding currents were specially designed. However, when the required welding current increased beyond the design parameters of a particular power supply, a higher capacity electric arc welder had to be designed and manufactured. For instance, electric arc welders having a maximum current of 1000-1500 amperes could not be used for a welding operation requiring 2000 amperes. As soon as a higher capacity welder was manufacture and made available, it was again limited by its maximum current capacity. Consequently, as increased current levels were demanded for a welding application, such as pike welding, custom design, expensive welders were often necessitated.
Since higher welding currents required newly designed and manufactured welders, field applications could not be optimized due to the limited current capacity of the available power supply. Attempts have been made to create a high capacity welders by connecting a plurality of low capacity welders to the output welding station. Such attempts were not successful because there was difficulty balancing the dynamic current sharing capabilities of two or more separate power supplies.